The present invention relates to an integral multifunctional system for motor vehicles, more specifically for those equipped with internal combustion engines and at least one auxiliary hydraulic mechanism and is applicable predominantly in the construction of passenger cars and lorries as well as buses.
Unknown is a system which similarly to the system of the present invention can perform simultaneously the following functions: utilisation of the energy of the exhaust gases, utilisation of the inertia energy when the driver voluntarily slows down the speed of the vehicle and/or its engine, supply of hydraulic liquid under pressure to auxiliary hydraulic mechanism(s) and collecting the liquid by the latter, as well as assisting the work of the starting system of the engine.
The following is known about the individual functions of the invention:
Turbo compound systems for internal combustion engines where the energy of the exhaust gases is utilized by a turbine which transforms the heat energy into mechanical energy and transfers it through a transmission as additional power to the engine shaft (U.S. Pat. No. 2,585,968, U.S. Pat. No. 4,586,337, U.S. Pat. No. 4,832,311 and U.S. Pat. No. 4,882,906). The basic problems facing the turbo compound systems are the big differences in the frequency of changing the momentary angular velocities and the momentary torque of the turbine and of the engine shaft and the fact that a high efficiency of the gas turbine is achieved at a relatively higher speed of rotation which, besides this, does not maintain a permanent relation with the speed of rotation of the engine shaft in different regimes of operation of the latter. The solution of these problems in some of the known turbo compound systems through a mechanical transmission with big and alternate transmission ratio and hydrodynamic clutch for clearing off the differences in the frequency of changing the momentary angular velocities (U.S. Pat. No. 2,585,968, U.S. Pat. No. 4,586,337, U.S. Pat. No. 4,832,311 and U.S. Pat. No. 4,882,906) lead to shortcomings such as to large volume, weight, complexity and price of the systems and low efficiency coefficient, and in one of the known systems (U.S. Pat. No. 4,832,311) additional shortcoming is the presence of voluminous, complex and unreliable regulated exhaust system of the engine.
Known from U.S. Pat. No. 4,805,409 and U.S. Pat. No. 4,894,992 are also turbo compound systems with electric transmission. Their shortcomings are the big weight and volume and low efficiency coefficient, as well as the complex and expensive devices for regulation of the speed of rotation of the electric engine and its coordination with the speed of rotation of the internal combustion engine.
Known is a turbo compound system (U.S. Pat. No. 5,079,913) with a combined mechanical and electric transmission. It combines the basic shortcomings of the systems with mechanical and systems with electric transmission.
Known are hydraulic systems which provide supply of hydraulic liquid under pressure to auxiliary hydraulic mechanism(s), most frequently a hydraulic booster of the steering system of the vehicle and collection of the liquid by it (them) (U.S. Pat. No. 5,505,276 and U.S. Pat. No. 5,749,431). They consist of a mechanical transmission through which a hydraulic pump is constantly operated by the engine and a hydraulic liquid tank. The shortcomings of such systems are: increased fuel consumption and respectively harmful emissions of the vehicle due to the permanent driving of the pump by the engine, including during most of the time when the auxiliary hydraulic mechanism is not in operation, as well as the circumstance that during the time in question the whole system represents a weight and volume ballast in which certain resources have been invested, but it is not used for useful functions.
Known is a regenerating brake system for vehicle (U.S. Pat. No. 5,050,936) consisting of distribution box located between the gear box and the main transmission of the vehicle connected through at least one electromagnetic clutch with a hydraulic machine which is connected with two hydraulic tanks for low and high pressure, valves, a multitude of sensors for the operative regimes of the engine and the basic brake system of the vehicle, as well as for the location of the brake pedal and a computer connected with the sensors, the valves for the hydraulic machine and the electromagnetic clutch(s). In regime of voluntary slowing down the speed of the vehicle by the driver the computer activates the electromagnetic clutch(s) and the hydraulic machine switches into a pump regime, whereas it operates as a brake which accumulates in the hydraulic tank for high pressure this part of the inertia energy of slowing down which has been transmitted to it. In subsequent acceleration of the vehicle the hydraulic machine switches on as an engine with a liquid from the hydraulic tank for high pressure and utilizes the accumulated energy by transmitting an additional torque to the outlet shaft of the transmission box of the vehicle. In uniform motion the electromagnetic clutch(s) switch out thereby disconnecting the mechanical connection between the transmission of the vehicle and the hydraulic machine. This system has several basic shortcomings. Due to the fact that the system is connected to the transmission of the vehicle after the transmission box, the system operates at low rotation speed and high torque which presupposes big weight and volume of its mechanical and hydraulic units. Besides, the system is complex, with a multitude of units but it fulfils no other functions. As a result, the weight, the volume and the price of the system and its maintenance are too high in comparison with the only function it performs during a relatively small part of the time of operation of the vehicle;
Systems for assisting the operation of the starting system of the engine at the time of its starting are not known.
The aim of the invention is to create an integral multifunctional system which can reduce the fuel consumption and respectively the harmful emissions of the vehicle provided with internal combustion engine through utilisation of the energy of the exhaust gases of the engine and the inertia energy when the driver voluntarily slows down the speed of the vehicle and/or its engine, simultaneously providing supply of hydraulic liquid under pressure to auxiliary hydraulic mechanisms of the vehicle and collection of the liquid by them, as well as to assist the operation of the starting system of the engine, providing at the same time a maximal simplicity and minimal volume, weight and price of the system through integrated multifunctional using of the prevailing part of its units.
The solution, according to the invention, is found by integral multifunctional system for motor vehicle provided with internal combustion engine and with at least one auxiliary hydraulic mechanism, where the system includes a tank for liquid connected with the outlet of the auxiliary hydraulic mechanism. Characteristic of the system is the fact that it consists of a hydraulic accumulator which, through electrically operated valve, is connected with the inlet of a hydraulic machine whose shaft is connected through a mechanical transmission with the engine shaft of the vehicle, and through a non-return valve the hydraulic accumulator is connected with the outlet of the hydraulic machine, and the hydraulic accumulator is also connected with the inlet of the auxiliary hydraulic mechanism(s). The outlet of the hydraulic machine, through another electrically operated valve, is connected with a hydraulic liquid tank which is also connected with the inlet of the hydraulic machine through a non-return valve, whereas the two electrically operated valves are connected electrically with a microcomputer which is also connected with a sensor for pressure and/or quantity of liquid hydraulically connected with the hydraulic accumulator and the microcomputer is connected with at least one sensor for the operative regime of the engine.
In one preferred embodiment the system includes a gas turbine fitted on the exhaust pipe of the engine of the vehicle, wherein the shaft of the gas turbine is mechanically connected with the shaft of a hydraulic pump and the hydraulic liquid tank is also connected with the inlet of the hydraulic pump whose outlet is connected with the hydraulic accumulator.
Suitable for this variant is for the shaft of the gas turbine to be connected with the shaft of the hydraulic pump through a mechanical transmission with reducing transmission ratio.
It is expedient, in these two variants, to provide between the hydraulic pump and the hydraulic accumulator a sensor for movement of the hydraulic liquid which is connected with the microcomputer.
In combination with the basic embodiment and/or with each of the above variants it is suitable to provide the hydraulic machine and/or the hydraulic pump with electrically operated mechanisms for regulation of the volume capacity, which mechanisms are electrically connected with the microcomputer.
Provided in combination with each of the above variants can be, between the inlet and the outlet of the gas turbine, a by-pass pipe for exhaust gases where a by-pass valve can be fitted.
With these variants the by-pass valve can have an electric operated opening mechanism, which mechanism must be connected electrically with the microcomputer which is also connected with two additional sensors for pressure of exhaust gases before and after the gas turbine.
The solution was also found by an integral multifunctional system for motor vehicle provided with an internal combustion engine, at least one auxiliary hydraulic mechanism and a microcomputer system for control of the operation of the engine consisting of at least one microcomputer connected with at least one sensor for the operative regime of the engine, where the integral multifunctional system includes a hydraulic liquid tank connected with the outlet of the auxiliary hydraulic mechanism and it is characterized by including a hydraulic accumulator which is connected, through an electrically operated valve, with the inlet of a hydraulic machine whose shaft is connected through a mechanical transmission with the shaft of the engine of the vehicle, and through a non-return valve the hydraulic accumulator is also connected with the outlet of the hydraulic machine, as the hydraulic accumulator is also connected with the inlet of the auxiliary hydraulic mechanism(s) and the outlet of the hydraulic machine, through another electrically operated valve is connected with the hydraulic liquid tank which is also connected with the inlet of the hydraulic machine through a non-return valve. The two electrically operated valves are connected electrically with the microcomputer which is also connected with a sensor for pressure and/or quantity of liquid, connected hydraulically with the hydraulic accumulator.
One of the variants of the integral multifunctional system includes a gas turbine fitted on the exhaust pipe of the engine of the vehicle, as the shaft of the gas turbine is mechanically connected with the shaft of a hydraulic pump and the hydraulic liquid tank is also connected with the inlet of the hydraulic pump whose outlet is connected with the hydraulic accumulator.
Suitable for this variant is for the shaft of the gas turbine to be connected with the shaft of the hydraulic pump through a mechanical transmission with reducing transmission ratio.
Possible, in combination with one of the above preferred variants, is the inclusion between the hydraulic pump and the hydraulic accumulator of a sensor for movement of the hydraulic liquid connected with the microcomputer.
Other preferred variants can be obtained through a combination of the characteristics of the basic variant and/or of the above preferred variants by a solution characterized by the fact that the hydraulic machine and/or the hydraulic pump are provided with electrically operated mechanisms for regulation of the volume capacity, which mechanisms are electrically connected with the microcomputer.
Other preferred embodiments of the system are characterized by the fact that between the inlet and the outlet of the gas turbine there is a by-pass pipe for exhaust gases where a by-pass valve is fitted.
Expedient with these variants is for the by-pass valve to have an electrically operated opening mechanism, which mechanism is electrically connected with the microcomputer, connected with whom are two additional sensors for pressure of the exhaust gases before and after the gas turbine.
The advantages of the system according to the invention are expressed in the following:
By virtue of the connections between the units of the system it provides a permanent supply to the auxiliary hydraulic mechanism(s) of hydraulic liquid under pressure from the hydraulic accumulator which is charged by the hydraulic pump and/or by the hydraulic machine when it operates in a pumping regime. The system also provides utilization of the energy of the exhaust gases through the gas turbine and the hydraulic transmission performed by the hydraulic pump, the hydraulic accumulator and the hydraulic machine when the latter operates in an engine regime, as a result from the opening of the electrically operated valves by the microcomputer. When the driver voluntarily slows down the speed of the vehicle and/or its engine the system also provides accumulation of a part of the inertia energy through the hydraulic machine operating in pumping regime and hydraulic accumulator and using the accumulated energy in subsequent acceleration of the vehicle through the hydraulic machine operating as an engine with a liquid from the hydraulic accumulator, as a result of opening the electrically operated valves by the microcomputer.
The system also provides the support of the starting system of the engine through the respective activation of the hydraulic machine as an engine in starting the engine in the presence of pressure and/or liquid in the hydraulic accumulator. In operating the system for utilization of the energy of the exhaust gases the hydraulic accumulator has two applications: as a damper which solves the problem of clearing off the difference in the frequency of changing the momentary angular velocities of the gas turbine and of the engine shaft; and as a tank for hydraulic liquid under pressure which solves, in certain periods of time, the problem of the necessity of inconstant transmission ratio between the gas turbine and the engine. The very transmission ratio is provided by the different volume capacities of the hydraulic pump and the hydraulic machine. In the variants of embodiment in which the volume capacity of the hydraulic machine and/or the hydraulic pump is regulated the problems related to the transmission ratio and its inconstant value are solved more precisely through respective regulation of the volume capacities by the microcomputer in the process of operation of the system.
The basic and principal advantage of the system according to the invention is its multifunctional nature. It performs the functions of all types of systems discussed above in the prior art section, having volume, weight, complexity and price comparable an even less than only one system of the discussed types. Besides, it also provides support to the starting system of the engine.
The system according to the invention has also advantages in comparison with each of the discussed systems individually as follows:
In comparison with the known turbo compound systems:
higher efficiency in utilizing the energy of the exhaust gases;
lesser weight, volume and price.
In comparison with the known hydraulic systems for feeding auxiliary hydraulic mechanisms of motor vehicles the advantages are that all units of the system are constantly engaged in useful functioning regardless of whether the auxiliary hydraulic mechanism operates at a certain moment, as well as the circumstance that it consumes power from the engine not constantly but only in rare and short periods of time.
In comparison with the known regenerating braking system the advantages are the simplified construction the reduced volume, weight and price, as well as the circumstance that during the time when the system does not operate as a regenerating braking system it performs other useful functions.